Reverse offset printing is a kind of offset printing method, which is an indirect printing method. In the reverse offset printing, a substrate (a subject for printing) is not directly printed on a plate, but, an elastic blanket acting as an intermediating function is coated with an ink, then unnecessary portions are taken off using a concavely patterned cliche, and then the ink remaining on the elastic blanket is printed onto the substrate. The offset printing uses the elastic blanket as a medium, so it may be applied to a hard substrate made of metal or glass, to which a direct printing method is not easily applied.
FIG. 1 is a schematic view showing a printing procedure for the conventional reverse offset printing. Referring to FIG. 1, a printing ink 112 is firstly applied to an elastic blanket cylinder 111, and then the elastic blanket cylinder 111 coated with the ink 112 is compressed to a hard cliche 115 such that an ink contacting with a relatively protruded embossed portion of the cliche 115 is removed by means of an embossed portion of the cliche 115. Then, the ink 112 remaining on the surface of the elastic blanket cylinder 111 is transcribed to a substrate 116 to form a fine pattern. After that, in order to repeat such a printing process, the hard cliche 115 is washed and dried such that the ink 112 stuck to the hard cliche 115 is removed to repeat such a printing process.
In case of the conventional offset printing method using the hard cliche 115, the cliche 115 should be washed and dried so as to repeat the printing process, which requires complicated procedure, consumes much time and increasing a printing cost. Thus, there have been continuous endeavors in the art to solve the above problems, and the present invention is designed under such circumstances.